Among activists who hack to make a point, some stay firmly on the right side of the law but others push the idea of civil disobedience to the limits.
Whatever the Chaos Computer Club's name suggests, Europe's largest hacker group is not intent on bedlam.
For CCC member Frank Rieger, the word hacking - the process of reconfiguring or reprogramming a system to do things that its inventor never intended - needs to be reclaimed, and stripped of negative connotations.
One of his club's main purposes is teaching gifted young people how to use hacking skills to bring about political change.
"We are trying to show people the beauty of technology, and how exciting it can be to find out new stuff and then do good things with that," he says.
This so-called "hacktivism" has been at the core of the German hacker community for more than 25 years.
For example, in 2008 the club obtained the then German interior minister Wolfgang Schauble's fingerprints from a glass, and published them in a format designed to fool fingerprint readers.
The aim was to point out the vulnerability of proposals for biometric identity systems.
But while the Chaos Computer Club's principles rule out attacks against websites, some other groups regard politically motivated attacks on computer systems as a legitimate form of online civil disobedience.
Earlier this year the group Anonymous launched a distributed denial of service attack (DDoS) on Australian government websites, protesting at plans to filter some kinds of pornography.
The attacks, which temporarily blocked access to some official websites, were condemned by the Australian government as "totally irresponsible".
A DDoS attack occurs when a website is bombarded by requests for pages - often by a network of computers under the control of the hacker - effectively taking it offline. They are illegal in many jurisdictions.
A season of reports exploring the extraordinary power of the internet, including:
Digital giants - top thinkers in the business on the future of the web
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.